Security locks



June 10, 1958 L TQRMA 2,838,748

SECURITY LOCKS Filed June 4, 1954 INVENTOR. Lou/5 Top/v4 ATTO/WWE? rates sEcUlurY LOCKS Louis Tenna, Bangor, Pa., assigner of one-half to Susan Horvath, Toronto, Ontario, Canada Application June 4, 1954, Serial No. 434,450

14 Claims. (Cl. 346-276) This invention relates to security locks and is directed particularly to an electro-mechanical mechanism for use in combination with a tumbler lock for rendering the lock pick-prooi and at the same time sounding an alarm if an attempt is made to open the lock with anything but a proper key.

The principal object of the invention is to provide a locking system of the character described suitable for use in 'locking and protecting homes, strong boxes, automobiles, and the like, and which sets off a continuous alarm if the lock is tampered with.

Another object is to provide a locking system of the character described having secret switch means whereby the alarm, once sounded, can be turned oit only by a person knowing the location of the switch.

Another object of this invention is to provide a lock system of the above nature wherein means is provided for locking the bolt to render the lock pick-proof.

A further object is to provide a system of the character described, readily adaptable for use with ordinary flat tumbler locks.

Another object of this invention is to provide a burglar alarm system for tumbler locks that is extremely simple, fool-proof, and effective in preventing burglary.

With these and other objects in View there is described herein one form in which the invention may be embodied in practice.

In the drawing wherein like figures denote corresponding parts throughout the several views:

Fig. l is a schematic representation of the burglar alarm system embodying the invention.

Fig. 2 is a side elevational view of a tumbler lock modiiied in accordance with the invention, showing the cover plate removed and thel bolt moved into locking position.

Fig'. 3 is a view similar to that shown in Fig. 2, but with the bolt in retracted position, and

Fig. 4 is a vertical cross-sectional View of the modied lock taken along the line /i-l of Fig. 2.

Referring now to the drawing in more detail, the burglar alarm system comprises a tumbler lock mechanism generally indicated byy the numeral 10, shown schematically in Fig. l and in greater etail in Figs. 2, 3 and 4, an electro-magnetic lock control device 11, an alarm device 12, a source of current supply 13, and a reset push button 1o.

The tumbler lock mechanism l@ can be an ordinary dat tumbler lock wherein the following modilications are made to adapt it to the purposes of the burglar alarm system comprising the invention. As illustrated in Figs. 2, 3 and 4 an upper edge portion of the casing 15 is cut out, as indicated by the numeral 16 to allow placement therein of a contact member 17 affixed to the outside of the lock and insulated therefrom by the insulation piece 18. The Contact member 17 is provided with an inwardly-extending dat contact surface portion l so disposed and spaced from the upper edges of the ilat tumbler members 2i? that the latter will not make contact with arent Patented June 10, 1958 said contact surface portion 19 when the proper key is used in the key cylinder to open or close the lock. More particularly, when the individual tumblers 20 are caused to move upwardly about the pin 22 against the counterclockwise biasing of their individual springs 23 by the turning of the proper key in the lock in the ordinary manner, they will move upwardly only far enough to allow release of the bolt 24 and continued turning of the key. The bolt 24 is thus moved from the unlocked position as illustrated in Fig. 3 to the locked position illustrated in Fig. 2. H wever, when an improper key or instrument is used in an attempt either to unlock or lock the lock mechanism 1d, over-travel of one or more of the tumblers Ztl invariably results, whereupon the whole metallic lock mechanism and housing is electrically connected .vith the Contact member 17 through mechanical engagement of the upper edges of any of said overtravelling tumblers with the Contact surface portion 19. hf/eans is rovided to sound an alarm when the lock 19 is tampered with as described above so that contact is made with the contact member i7, said means comprising an electric circuit including the alarm device i2, the source of current 13, and the normally-closed push button switch it. The electric circuit (see Fig. l) comprises a conductor 2S interconnecting the position terminal of the source iT; with terminal of the push button 14, a conductor 26 interconnecting the other terminal ol' said push button with one terminal of the alarm device 12, a conductor 27 interconnecting the other terminal of said alarm device with the contact member 17 and a conductor 2S connecting the negative or ground side of the electronic source i3 with tie metallic casing 15. When contact between one or more of the tumblers 26 and the Contact surface portion l@ of the contact member 17 is made as described above, a circuit is completed to energize the alarm device l2, said circuit being from the source i3 through the normallyeclosed push button switch i to one terminal ci the alarm device, and from the other terminal oi the alarm device through the contact portion lil, through one or more of the tumblers 20 through the metallic parts or" the lock to the casing, through the conductor 23 back to the ground terminal of the source.

A locking circuit means is also provided to keep the alarm device 12 energized even after contact with the contact member l/ is broken, said means comprising an electro-magnet connected by leads Si?, 3l across the conductors 25, 2.7 of said alarm device to be energized sinuiltaneously therewith. Associated with the electroiet is an armature 32- resiliently ixed at one end to the lock casing t as indicated by the numeral and adapted to be voi/'ed up ardly (Fig. l) by the attractive torce of said electro-magnet when energized.

The armature is provided with an electrical Contact S4 cooperatively mounted with respect to a fixed contact 35 so as to make contact therewith when the armature is moved up due to energization of the electromagnet. The iixed cor -/t is insulated from the casing 1S by an intermediate insulation piece 3d and connected by conductor 37 to the conductor 2'?. Thus, once the as described above, and the electro-magnet 2"? energized, a second euergization circuit provided o keep the alarm device and electromagnet energized even after opening or the original circuit through the Contact member i7. This secondary circuit can te traced from the ground terminal of the source i3, through conductor 2S to the metallic lock casing i5, through the armature 32, closed contacts 34, S5, conductors 37 and 27 to one terminal of the alarm device 12, and from the other terminal thereof back through the normally closed push button switch 1d to the positive terminal of the source 13.

Means is also providedV to positively prevent withdrawalof the lock bolt24 after the alarm device 12 has been set cfr' and the electro-magnet 29 energized. The end of the armature V32 has an upwardly-extending abutment portion 41 adapted to be moved up behind the bolt 24 (see Fig. 2) when said armature is drawn upward upon energization of the electro-magnet. As illustrated in Figs. 2 and 3 the side of the lock casing 15 may be provided with an opening 42 through which the armature 32 extends.

As explained above, when the lock has been tampered with in an attempt to open or close it with an irnproper key or with a tool, the alarm will be set off and the abutment portion 41 of the armature 32 will be moved upwardly to prevent withdrawal of the lock bolt 24 even by means of the correct key. lMoreover the alarm 12 and the electro-magnet 29 will continue to be energized until the push button 14 is actuated to openV an electric bell, it will be understood, of course, that it could as well be a buzzer, chime, phonograph, tape recorder, signal light, or any other electrically operated indicating device.

While there has been disclosed in the specification one form in which the invention may be embodied in practice, it is to be understood that this form is shown for the purpose of illustration only, and that the invention is not to be limited to the specific disclosure but may be Ymodified and embodied in various other forms without departing from its spirit. In short the invention con- Vtains all the modications and embodiments coming within the scope of the following claims.

I claim:

l. A lock comprising a bolt, key receiving means, key operated tumbler means to permit movement of said bolt from unlocked to locked position when a correct key is inserted into said key receiving means and turned, said tumbler means including means to prevent turning of any key other than the correct key inserted into said key receiving means to prevent retraction of the bolt from locked to unlocked position, an electric alarm, means controlled by said tumbler means to actuate said alarm upon inserting a key other than said correct key into said key receiving means after said bolt has been moved to locked position by insertion of a correct key into said key receiving means and turning of said correct key, means to retain said alarm in actuated condition upon subsequent removal of said other key from said keytreceiving means, and means controlled by Vsaid retaining means to block said bolt and prevent unlocking of said bolt by insertion of a correct key into Vsaid key receiving means and turning the same after said other key has been removed from said key receiving means.

2. The combination of claim l, in combination with electrically actuated switch Vcontrol means to render said alarm inoperative after said alarm has been actuated, and to release said retaining means and said blocking means.

3. A lock comprising a bolt, key control means to move the bolt, tumbler means controlled by said key control means and movable to a position for releasing the lbolt so that it can be moved to locked position by the key control means, saidtumbler means being movable to a second position when a wrong key is inserted in the key control means, an electric alarm, a circuit sesame for said alarm including a"switch adapted to be closed for actuating the alarm upon inserting a Wrong key thereby moving said tumbler means to said second position, means to retain said alarm in actuated condition even upon removal of said wrong key and release of said switch means, and means to retain said bolt from being retracted from locking position by a correct key inserted into said key actuated means after said alarm has been actuated.

4. A lock comprising a bolt, key control means to move the bolt, tumblerV means controlled by said key control means and movable to a position for releasing the bolt so that it can be moved to locked position by the key control means, said tumbler means being movable to a second position when a wrong key is inserted in the key control means, an electric alarm, a circuit for said alarm including a switch adapted to be closed for actuating the alarm upon inserting a wrongkey and moving said tumbler means to said second position, means to retain said alarm in actuated condition even upon removal of said wrong key and release of said switch means, means `to retain said bolt from being retracted from locking position by a correct key inserted into said key actuated means after said alarm has been actuated, and a second switch means to render the alarm inoperative. I

5. A lock comprising a bolt, key control means to move lthe bolt, tumbler means controlled by said key controlmeans and movable to a position for releasing the bolt so that it can be moved to locked position by the key control means, said tumbler means being movable to a second position when a wrong key is inserted in the key control means, an electric alarm, a circuit for said alarm including a switch adapted to be closed for actuating the alarm upon inserting a wrong key and moving said tumbler means to said second position, means to retain said alarm in 'actuated condition even upon removal of said wrong key and release of said switch means, means to retain said bolt from being retracted from locking position by a correct key inserted into said key actuated means after said alarm has been actuated, and a second switch means to render the alarm inoperative, said second switch means being in said circuit and being manually controlled.

6. A security lock comprising a bolt movable between locked and unlocked positions, a plurality of tumblers,

echanical means interconnecting said bolt and tumblers and including a tumbler-actuating key to selectively secure said bolt in one or the other of said positions, and

electric means for signalling when an attempt is made to actuate said tumblers to move said bolt without the use of said key, wherein said electric means comprisesA an electric circuit, .a current source in said circuit, an alarm device in said circuit, and a contact member disposed so as to be contacted by one of said tumblers when moved beyond the distance required for actuation thereof by said key for moving said bolt, said contact members and said tumblers forming a switch and being connected in said circuit, including a secondary circuit comprising an electro-magnet connected in parallel with said alarm device, a spring-biased armature cooperating with said electro-magnet to be moved when'said electromagnet'is energized, a movable electrical contact on said armature, a fixed electrical contact adapted to be engaged by said movable contact when said armature is in moved position, andrmeans connecting said fixed and movable contacts in parallel with the switch formed by said tumblers and said contact member, whereby said alarm device is continuously energized even after opencircuiting of the switch formed by said tumblers and contact member.

ergization of the circuit to said electro-magnet.

8. The combination of claim 6 including mechanical means cooperative with said electro-magnet for preventing movement of said bolt from locked to unlocked position when said electro-magnet is energized.

9. The combination of claim 6 including an abutment on one end of said armature and abuttable against an end of said bolt when in locked position to prevent movement of said bolt to unlocked position when said armature is in moved position as a result of said energization of said electro-magnet.

10.An electro-mechanical security lock system for use in cooperation with locks of the flat tumbler type comprising a contact member disposed to be contacted by one of the tumblers of the lock when moved beyond its normal position in opening or closing the lock, an electric series circuit, a current source in said circuit, an electric alarm device in said circuit, said contact mem- .ber and the tumblers forming a normally open switch in said circuit, whereby said alarm device is energized when one of the tumblers is moved beyond its ordinary position in opening or closing the lock, including a secondary circuit comprising an electro-magnet, connected in parallel with said alarm device, a spring-biased armature cooperating with said electro-magnet to be moved when said electro-magnet is energized, a movable electrical contact on said armature, a fixed electrical contact adapted to be engaged by said movable Contact when said armature is in moved position, and means connecting said fixed and movable contacts in parallel with the switch formed by said tumblers and said contact member, whereby said electro-magnetic lock control device is continuously energized even after open circuiting of the switch formed by said tumblers and contact member, including a normally closed switch in said circuit operative to break the energization of the circuit to said electromagnet, including mechanical means cooperating with said electro-magnet for preventing movement of said bolt from locked to unlocked position when said electromagnet is energized.

11. The invention as defined in claim 10 including an abutment on one end of said armature and abuttable against an end of said bolt when in locked position to prevent movement of said bolt to unlocked position when said armature is in moved position as a result of energization oi said electro-magnet.

12. The combination of claim 10 including an abutment on one end of said armature and abuttable against an end of said bolt when in locked position to prevent movement or said bolt to unlocked position when said armature is in moved position as a result of energization of said electro-magnet.

13. A lock comprising a bolt, key receiving means, key operated tumbler means to permit movement of said bolt from unlocked to locked position when a correct key is inserted into said key receiving means and turned, said tumbler means including means to prevent turning of an incorrect key inserted into the key receiving means to thereby prevent retraction of the bolt from locking to unlocking position, and means to block said bolt and prevent unlocking of said bolt by a correct key being inserted into the key receiving means and turned, after an incorrect key inserted into the key receiving means has been removed therefrom.

14. The combination of claim 13, in combination with a manually actuated means to release said blocking means.

References Cited in the tile of this patent UNITED STATES PATENTS 547,007 Frizelle Oct. 1, 1895 830,780 Glass Sept. 11, 1906 1,223,060 Louthan Apr. 17, 1917 2,057,301 Golokow Oct. 13, 1936 2,295,178 Kolias Sept. 8, 1942 2,051,301 Louthan Sept. 18, 1945 2.617868 Menkin Nov. 1l, 1952 

